1. Field of the Invention
The present invention relates to breathable seats used for seats, chairs, etc. in means of transportation, such as cars, watercraft, aircraft, etc.
2. Description of the Related Art
Described in Jpn. Pat. Appln. KOKOKU Publication No. 4-14848 (prior art 1) and Jpn. UM Appln. KOKOKU Publication No. 6-12688 (prior art 2) are breathable seats that are formed of a fibrous cushion (fibrous layer) and urethane foam molded integrally with each other. In the seat described in the prior art 1, the fibrous layer is pushed by a foaming pressure that is produced as a stock solution of urethane foam is injected for molding. When the seat is removed from a mold, the fibrous layer is released from the foaming pressure of the urethane foam and restored, so that it cannot obtain given dimensions. In the seat described in the prior art 2, the urethane foam stock solution gets into the fibrous layer as it foams, so that the boundary between the fibrous layer and the urethane foam hardens. Since the seat cannot easily obtain a satisfactory foaming pressure, moreover, it cannot enjoy necessary hardness for a cushion body.
On the other hand, a seat that is described in Jpn. Pat. Appln. KOKAI Publication No. 10-248685 (prior art 3) is a composite structure that combines a fibrous resilient body and urethane foam. This seat comprises an obverse pad layer formed of the fibrous resilient body and a reverse pad layer formed of the urethane foam on the back of the obverse pad layer. The obverse pad layer has a substantially fixed thickness throughout its area. According to this seat, the density of the fibrous resilient body is subject to little dispersion, and the hot-molding time can be shortened. As compared with a full-form structure of a fibrous resilient body, the composite-structure seat is improved in flexibility and hardness.
However, these conventional seats cannot be satisfactorily prevented from becoming nonbreathing and cannot readily enjoy good cushioning properties.